Three electromagnetic waves travel through a certain point P along an x axis. They are polarized parallel

Question:

Three electromagnetic waves travel through a certain point P along an x axis. They are polarized parallel to a y axis, with the following variations in their amplitudes. Find their resultant at P.
E1 = (10.0μV/m) sin [(2.0 x 1014 rad/s)t]
E2 = (5.00μV/m) sin [(2.0 x 1014 rad/s)t + 45.0 o]
E3 = (5.00μV/m) sin [(2.0 x 1014 rad/s)t – 45.0o]